With 45 two-hour shows full of elevated platforms, trap doors and more nostalgia than you can handle, it's no wonder that the guys of NKOTB are still in business after three decades.

The Main Event tour kicked off on Friday, May 1 and their fans are more dedicated than ever. The tried-and-true followers, called Blockheads, have idolized the men since they were a boy band. Two such devotees, Oni and Trixie, got to meet their idols backstage.

Also on the tour are fellow '90s chart-toppers TLC and rapper Nelly.

"We worked with TLC before on a one-off show and hit it off great with them," NKOTB's Donnie Wahlberg told ET last month. "It kinda started dawning on us, you know, one of the bigger boy bands in history and the biggest girl band in history would be a great marriage to go on tour together."

The ladies told us when it comes to their on-stage wardrobe, it's all about comfort over style.

"TLC does not dance in heels," Chilli told ET. "This is what we dance in, because we dance like crazy and if we danced in high heels we would break our ankles and it would not be good, so this is what we wear."